/ Dictionary / Index K known quantity: Meaning and Definition of Find definitions for: known' quan'tity Pronunciation: [key] a quantity whose value is given: in algebra, frequently represented by a letter from the first part of the alphabet, as a, b, or c. any factor, circumstance, etc., that is already accepted or familiar: Her honesty is a known quantity. Random House Unabridged Dictionary, Copyright © 1997, by Random House, Inc., on Infoplease. know-nothing Knox Related Content Daily Word Quiz: benevolent Analogy of the Day: Today’s Analogy Spelling Bee: Today’s Spelling Bee Frequently Misspelled Words Frequently Mispronounced Words Easily Confused Words Writing & Language